The Circulatory System Lesson 2: Composition and Function of Blood 27 The Circulatory System Lesson 2: Composition and Function of Blood

Lesson Objectives Upon completion of this lesson, students should be able to … Define and spell the terms to learn for this chapter. List and describe the components of blood. Discuss the importance of blood typing and cite which blood types are compatible. State the difference between Rh-positive blood and Rh-negative blood.

Blood Average adult has about 5 liters of blood Circulates through body within vessels of cardiovascular system Is a mixture of plasma with cells The cells are called formed elements: Erythrocytes Leukocytes Platelets 3

Functions of Blood Transportation Defense Regulation 4

Plasma is about 55% of the total blood components.

The remaining part of blood is composed of formed elements. 6

Formed Elements of Blood 7

Erythrocytes (Red Blood Cells) Enucleated–no nucleus Hemoglobin gives red color 5 million per cubic millimeter of blood Adult has 35 trillion Life span of 120 days Then spleen removes worn out ones, iron can be reused, bilirubin is disposed of by liver 8

Leukocytes White blood cells Provide protection against pathogens Bacteria Viruses Foreign material Spherical shape with nucleus 8,000 per cubic millimeter of blood 9

Leukocyte Classification Granulocytes Basophils – Release histamine and heparin to damaged tissue Eosinophils – Destroy parasites and increase during allergic reaction Neutrophils – Important for phagocytosis Agranulocytes Monocytes – Important for phagocytosis Lymphocytes – Provide protection through immunity 10

Neutrophils The most common leukocyte Categorized as granulocytes Have many lobes Known as polymorphonucleated leukocytes (PMN) or poly Develop in the red marrow Live a few days or even a few hours if they are actively destroying bacteria 11

Neutrophils A neutrophil has cytoplasm that contains granules that do not readily stain with either a red or blue dye. It has a nucleus with three or more lobes. 12

Eosinophils One of the least common leukocytes Categorized as granulocytes; also known as eosinophils Develop in the red marrow Engulf and destroy foreign cells (pollen, animal dander, and so forth) Release toxic chemicals that kill parasites that invade the body 13

Eosinophils An eosinophil has cytoplasm that contains granules that stain bright pink to red. It has a nucleus with two lobes. 14

Basophils One of the least common leukocytes Categorized as granulocytes Nucleus of a basophil has 2 lobes Develop in the red marrow Release histamine at the site of tissue damage Release heparin, an anticoagulant 15

Basophils A basophil has cytoplasm that contains granules that stain dark blue to purple. It has a nucleus with more than one lobe. 16

Lymphocytes Second most common leukocyte Categorized as agranulocytes because the granules in their cytoplasm are nearly invisible Some lymphocytes live for just a few days, while others live for many years Begin their development in the red marrow Present in the blood and in the lymph nodes, lymphoid tissues, and organs of the lymphatic system 17

Lymphocytes A lymphocyte has little cytoplasm with nearly invisible granules and a round nucleus. 18

Monocytes One of the least common leukocytes Categorized as agranulocytes because the granules in their cytoplasm are nearly invisible Have a large amount of cytoplasm, and the nucleus is shaped like a kidney bean Develop in the red marrow Are phagocytes that engulf and destroy all types of invading microorganisms, cancerous cells, dead leukocytes, and cellular debris Found in the blood and in the lymph nodes of the lymphatic system 19

Monocytes A monocyte has cytoplasm with nearly invisible granules and a kidney bean-shaped nucleus. 20

Thrombocytes (Platelets) Different from other blood cells because they are only cell fragments Active in the blood clotting process Begin in the red marrow as stem cells that then become megakaryoblasts The cytoplasm of the megakaryocyte constantly breaks away at the edge to form the cell fragments that are released into the blood 21

Thrombocytes (Platelets) Smallest of all blood elements Not whole cells 200,000-300,000 per cubic millimeter Critical in clotting or hemostasis Agglutinate into small clusters Leads to formation of thrombin, which converts fibrinogen to fibrin 22

Blood Typing Each person’s blood is different from others’ due to the presence of marker proteins on the surface of his/her erythrocytes Before a person receives a blood transfusion it is important to do a blood typing This is a laboratory test to determine if the donated blood is compatible with the recipient’s blood There are many different subgroups of blood markers, but the two most important ones are the ABO system and Rh factor 23

ABO System There are two possible RBC markers, A and B A person with an A marker is said to have type A blood. Type A blood produces anti-B antibodies The presence of a B marker gives type B blood and anti-A antibodies 24

ABO System Absence of either an A or a B marker results in type O blood, which contains both anti-A and anti-B antibodies If both markers are present, the blood is type AB and does not result in any antibodies 25

Blood Types Antigens Type A Type B Four blood types A B AB O 26

Universal Donor Because type O blood does not have either marker A or B, it will not react with anti-A or anti-B antibodies For this reason a person with type O blood is referred to as a universal donor In an emergency, type O blood may be given to a person with any of the other blood types A person with type AB blood has no antibodies against the other blood types and therefore, in an emergency, can receive any type of blood. They are universal recipients. 27

Rh Factor A person with the Rh factor on his/her red blood cells is said to be Rh-positive (Rh+) Since this person has the factor, he/she will not make anti-Rh antibodies A person without the Rh factor is Rh-negative (Rh-) and will produce anti-Rh antibodies Therefore, an Rh+ person may receive both an Rh+ and an Rh- transfusion, but an Rh- person can receive only Rh- blood 28

Questions? 29